by 1972nail » Thu Jun 21, 2018 10:08 am
The tick over should be low enough not to make the advance weights to come into play. If they are just beginning to advance then the timing can behave like this, especially if the weights are sticky. Slow the tick over down and see if it stabilises. You should also have the vacuum pipe disconnected and the vacuum pipe to the carb plugged to keep the mixture stable.
Editor of the VVOC Magazine ReVival
"When you have a Firenza like mine, who needs any Minis?" copyright David Maxwell 1979.